Roughness of retinal layers in Alzheimer’s disease

There is growing evidence that thinned retinal regions are interspersed with thickened regions in all retinal layers of patients with Alzheimer’s disease (AD), causing roughness to appear on layer thickness maps. The hypothesis is that roughness of retinal layers, assessed by the fractal dimension (FD) of their thickness maps, is an early biomarker of AD. Ten retinal layers have been studied in macular volumes of optical coherence tomography from 24 healthy volunteers and 19 patients with mild AD (Mini-Mental State Examination 23.42 ± 3.11). Results show that FD of retinal layers is greater in the AD group, the differences being statistically significant (p < 0.05). Correlation of layer FD with cognitive score, visual acuity and age reach statistical significance at 7 layers. Nearly all (44 out of 45) FD correlations among layers are positive and half of them reached statistical significance (p < 0.05). Factor analysis unveiled two independent factors identified as the dysregulation of the choroidal vascular network and the retinal inflammatory process. Conclusions: surface roughness is a holistic feature of retinal layers that can be assessed by the FD of their thickness maps and it is an early biomarker of AD

Visual motion discrimination experiments reveal small differences between males and females

10 pags., 5 figs., 8 tabs.Recent results have shown that males have lower duration thresholds for motion direction discrimination than females. Measuring contrast thresholds, a previous study has shown that males have a greater sensitivity to fine details and fast flickering stimuli than females, and that females have a higher sensitivity to low spatial frequencies modulated at low temporal frequencies. Here, we present the data of a contrast-detection motion discrimination experiment and a reanalysis of four different motion discrimination experiments where we compare duration thresholds for males and females using different spatial frequencies, stimulus sizes, contrasts, and temporal frequencies (in two experiments, motion surround suppression was measured). Results from the main experiment and the reanalysis show that, in general, the association between sex and contrast and duration thresholds for motion discrimination is not significant, with males and females showing similar data patterns. Only the reanalysis of one out of four studies revealed different duration thresholds between males and females paired with a strong effect size supporting previous results in the literature, although motion surround suppression was identical between groups. Importantly, most of our results do not show significant differences between males and females in contrast and duration thresholds, suggesting that the sex variable may not be as relevant as previously claimed when testing visual motion discrimination.Supported by grant PID2021-122245NB-I00 from Ministerio de Ciencia e Innovación (Spain) to ISP. The funding source was not involved in the preparation of this article. RL is supported by a Juan de la Cierva-Formación fellowship (FJC2020-044084-I) funded by MCIN/AEI /10.13039/501100011033 and by the European Union Next Generation EU/PRTR.Peer reviewe

Visual motion discrimination experiments reveal small differences between males and females

Recent results have shown that males have lower duration thresholds for motion direction discrimination than females. Measuring contrast thresholds, a previous study has shown that males have a greater sensitivity to fine details and fast flickering stimuli than females, and that females have a higher sensitivity to low spatial frequencies modulated at low temporal frequencies. Here, we present the data of a contrast-detection motion discrimination experiment and a reanalysis of four different motion discrimination experiments where we compare duration thresholds for males and females using different spatial frequencies, stimulus sizes, contrasts, and temporal frequencies (in two experiments, motion surround suppression was measured). Results from the main experiment and the reanalysis show that, in general, the association between sex and contrast and duration thresholds for motion discrimination is not significant, with males and females showing similar data patterns. Only the reanalysis of one out of four studies revealed different duration thresholds between males and females paired with a strong effect size supporting previous results in the literature, although motion surround suppression was identical between groups. Importantly, most of our results do not show significant differences between males and females in contrast and duration thresholds, suggesting that the sex variable may not be as relevant as previously claimed when testing visual motion discrimination.Depto. de Psicología Experimental, Procesos Cognitivos y LogopediaFac. de PsicologíaTRUEpu

"Suppression of optokinesis" paper demos

Demonstration of paradigm used in the paper "Suppression of optokinesis"When tracking an object moving against a textured background, the background retinal image moves opposite to the smooth pursuit eye movement direction. Ocular following responses to background motion in the direction of this reafferent signal are suppressed compared to motion in the direction of pursuit. To understand how these responses are suppressed, we varied the contrast of the background to tell apart two plausible accounts.</p

Matlab libraries for the execution of sensory and perceptual practices both inside and outside the classroom

El Proyecto de Innovación Docente consta de 17 programas en Matlab que corresponden a experimentos clásicos de psicofísica visual y auditiva (e.g. curva de audibilidad, función de sensibilidad al contraste, bandas críticas auditivas, determinación de los parámetros de la Ley potencial de Stevens para brillo y sonoridad, etc.) y a programas de análisis de resultados experimentales. Los programas son originales, ejecutables en tiempo real y de uso intuitivo para que el estudiante pueda realizar, en el aula y en remoto, prácticas sensoriales y perceptivas que son obligatorias en asignaturas como Psicología de la Percepción y Arquitectura Funcional de la Mente entre otras. En el Anexo de este documento se presentan capturas de los interfaces gráficos de estos programas junto con una breve descripción de sus objetivos, características, y funcionalidades. Todos los programas están sujetos a mejoras que se irán añadiendo en sucesivas versiones. Las actualizaciones de estos programas se harán accesibles en esta página web: https://www.ucm.es/serranopedrazalab/.This Teaching Innovation Project consists of 17 Matlab programs that correspond to classical experiments in visual and auditory psychophysics (e.g., audibility curve, contrast sensitivity function, auditory critical bands, determination of parameters for Stevens' Power Law for brightness and loudness, etc.) and programs for the analysis of experimental results. The programs are original, executable in real-time, and intuitively designed for students to conduct sensory and perceptual practices, both in the classroom and remotely. These practices are mandatory in subjects such as Psychology of Perception and Functional Architecture of the Mind, among others. In the Annex of this document, screenshots of the graphical interfaces of these programs are presented, along with a brief description of their objectives, features, and functionalities. All programs are subject to improvements that will be added in successive versions. Updates to these programs will be made accessible on this website: https://www.ucm.es/serranopedrazalab/."Depto. de Psicología Experimental, Procesos Cognitivos y LogopediaFac. de PsicologíaFALSEsubmitte

Professional equipment for conducting Perception Psychology practice (Bachelor's Degree in Psychology) and complementary activities in Biological Physics (Master's Degree in Biomedical Physics)

Depto. de Psicología Experimental, Procesos Cognitivos y LogopediaDepto. de Estructura de la Materia, Física Térmica y ElectrónicaFac. de PsicologíaFac. de Ciencias FísicasFALSEsubmitte